Title : Sustainable Fe(III)/Fe(II) cycles triggered by co-catalyst of weak electrical current in Fe(III)/peroxymonosulfate system: Collaboration of radical and non-radical mechanisms
Abstract:
Recently, advanced oxidation processes based on peroxymonosulfate (PMS-AOPs) have garnered attention for their efficient elimination of various persistent organic contaminants, owing to the excellent oxidizing ability and long lifespan of sulfate radical. The high degradation efficiency is rooted in the continuous activation of PMS by transition metals like Fe or Co. However, many systems encounter the issue of catalyst accumulation in the high-price state, leading to deactivation. Traditional cocatalysts such as MoS2, Mn single-atom, and hydroxylamine can promote the circulation of catalyst redox pairs, yet they pose a secondary pollution problem. The electrochemical oxidation process (EC) serves as a common AOPs for degrading pollutants through an environment-friendly electric field. The cathode region in the EC functions similarly to a cocatalyst. Therefore, an electrochemical process was utilized to establish an EC/Fe(III)/PMS system for sulfamethoxazole (SMX) degradation, aiming for the future treatment of hospital wastewater. The entire study has been completed to achieve the following objectives:
(1) Evaluation of the feasibility and performance of EC/Fe(III)/PMS process for SMX degradation.
(2) Exploration of the origin and generation mechanisms of involved reactive oxygen species (ROS) to evaluate their respective contributions to SMX oxidation.
(3) Identification of degradation byproducts in this system to indicate probable degradation pathways.
(4) Estimation of the effectiveness and endurance of the EC/Fe(III)/PMS system and its capacity to inactivate pathogens for future treatment of raw hospital wastewater.
An electrochemical system was constructed used a dimensional stable anode (DSA) and carbon felt cathode (CF). The non-toxic transition metal Fe is circulated by the electric field to promote the continuous activation of PMS. The experimental methodology was established for the following purposes. (1) System oxidation mechanism. Probe experiment and quenching experiment were conducted to reveal the types of active species. Kinetic competition experiments were carried out to study the oxidation contribution of active species. Electron paramagnetic resonance (EPR) analysis and electrochemical analysis were utilized to investigate the generation pathways of active species. (2) Practical application. Life tests, degradation tests of different pollutants and influence tests of coexistence ions were conducted to evaluate the stability of the system. Bactericidal experiments of E. coli and the actual hospital wastewater degradation experiment were performed to assess the synchronous bactericidal degradation ability. (3) Pollutant degradation mechanisms. The high-resolution mass spectrometry (MS) combined with density functional theory (DFT) was used to deduce the degradation pathways of organic pollutant. Toxicological analysis software and acute toxicity tests were employed to study the effects of by-products on the environment.
EC/Fe(III)/PMS process represents a fusion of electrocatalysis and Fenton-like technology, harnessing electron transfer to drive oxidation and activate PMS synergistically under low-energy consumption conditions. This system comprises various active substances and establishes a sophisticated pollutant degradation mechanism capable of addressing the complexities of real-world water bodies. It demonstrates the capability for synchronous elimination of pathogens. This study not only introduces a novel equipment setup but also delves deeply into the reaction mechanism, providing a robust theoretical foundation for subsequent related research endeavors.
Keywords:Electrocatalyticreaction;Peroxymonosulfate;Fe(III)/Fe(II)cycle;Oxidation mechanism
Audience Take Away
- This presentation is poised to captivate researchers primarily focused on the development of electrocatalytic systems and their implementation in real-world environmental engineering applications.
- This presentation provides insight into the principles and mechanisms underlying electrochemical catalytic reactions.
- This study not only introduces a novel equipment setup but also delves deeply into the reaction mechanism, providing a robust theoretical foundation for subsequent related research endeavors.
- This presentation is a good inspiration for aspiring practitioners of electrocatalytic technologies.
